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(No Model.) 4 Sheets-Sheet 1. A. J. SHAW, Deod M. H. SHAW,Administratrix.

CRANE.

Patentedl Jan. 5, 1897,

(No Model.) 4 Sheets-Sheet 2. A. J. SHAW, Decd M. H. SHAW,Administratrix.

- CRANE,

Patented' Jan. 5,A 1897.

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No.15'74,581. Patented Jan'. 5, 1897.

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A. J. SHAW', Dem

M. H. SHAW, Administratrix.

URANB. Y N. 5'74,51. Patented Jan. v5, 1897. f

@htm/mmf NITED- STATESY .PATENT OFFICE.

ALTON J. SHAW, OF MUSKEGON, MICHIGAN; MARY H. SHAWV, ADMINISTRA- TRIX OFSAID ALTON J. SHAV, DECEASED, ASSIGNOR TO THE SHAW ELECTRIC CRANECOMPANY, OF SAME PLACE.

CRANE.

SPECIFICATION forming part of Letters Patent N o. 574,581, dated.January 5, 1897. Application filed December 13, 1894. Serial No.531,711. (No model.)

To all whom t may concern:

Be it known that l, ALTON J. SHAW, a citizen of the United States,residing at Muskegon, in the county of Muskegon and State of Michigan,have invented certain new and useful Improvements in Cranes, of whichthe following is a specification.

My invention consists in a novel construction and arrangement of thegirders or bridges Io of traveling bridge-cranes whereby the lateralvibration to which they have hitherto generally been subject isprevented and torsional strain is reduced.

The invention is illustrated in the accompanying drawings, in Which-Figure l is a perspective View of one side of a bridge constructed inaccordance with my invention. Fig. 2 is a top plan view of a portion ofmy improved bridge or girder zo partially broken away to show partsotherwise hidden. Fig. 3 is a side elevation; Fig. 4, a verticaltransverse section of the same; and Figs. 5, 6, and 7 illustrate certainmodiications.

2 5 In traveling bridge-girders and like structures in which a bridgebeam or girder is supported at its ends and is moved by power applied ator near its ends there is quite serious lateral strain and deflection instarting 3o and a greater or less lateral vibration during travel due tothe inertia of the bridge itself, augmented by that of the load carriedbetween its ends. In other words, when power is applied to thetruck-Wheels they start for- Ward promptly, while the intermediatebridge or girder does not start with equal promptness, but comes intomotion gradually from the ends toward the middle. in time, thoughslightJ is proportionate to the 4o length of span, weight and rigidityof structure, and weight and location of load, being of course greatestwhen the span is long, the structure deficient in rigidity, the loadgreat, and its location near the mid-length of the bridge.

To overcome or prevent the lateral deflection of the bridge or girder,it has been proposed to truss the same laterally or horizontally, and inorder to avoid transferring the 5o strains of the horizontal truss orbracing to The difference the vertical face of the bridge beam or girderand to preclude torsional strains it has been proposed to arrange thehorizontal truss to bear only against the iiange-plates or the upper andlower chords of the bridge and to employ a vertical truss to connect andcarry the upper and lower horizontal trusses, said vertical truss to becarried at its ends by supplemental supports at or near the ends ot' themain bridge or girder. This produces in ef- 6o feet an open box-girderor two vertical girders connected at their upper and lower chords byhorizontal trusses, but without any other cross connection.

Under my construction the secondary vertical truss is dispensed with andthe lower horizontal truss is suspended from the outer chord of theupper horizontal truss, which latter is carried by struts extendingupward and outward from the lower chord of thel 7o main bridge beam orgirder, or the lower horizontal truss is suspended by Adiagonalsextending downward and outward from the upper chord of the main bridge,and the upper horizontal truss is supported upon the lower one bysuitable uprights. This construction prevents any material lateraldeiiection and vibration of the bridge, and the weight of the outerbeams of the horizontal trusses is mainly sustained by being trans- 8olated by said diagonals into horizontal stresses in the horizontaltrusses themselves.

In this way the main girder is relieved from torsional stresses almostif not quite as effeotually as if an outer or auxiliary girder wereused, and certain advantages are gained which will be hereinafter setforth.

As is well understood, when a girder or beam is loaded vertically andsymmetrically or in a transverse plane through its center of 9o gravitythe effect of such loading is to compress or shorten the upper andelongate the lower flange or chord of the girder without torsionaleffect. If, therefore, there be rigid n horizontal connections from suchgirder to another vertical girder which does not receive the load, andhence is not similarly deflected, such connections will tend to throweither the main or the secondary girder out of shape laterally or toproduce a torsional strain upon roo one or both. If, instead ofemploying a second vertical girder, the main gird er be merely stiffenedlaterally by horizontal trusses carried by diagonal struts or bracesextending` upward from the lower chord of the main girder, there will beno lateral deflection of the main girder by a symmetrically-applied loadand little or no torsional effect thereon, as the trusses will merelyyield vertically and adapt themselves to the vertical deflection of themain girder.

In practice a crane-bridge commonly comprises two beams or girders,which support the trolley on rails situated on their top directly overtheir centers of gravity. In some cases the load is not supporteddirectly over the center of gravity of the girders, and more or lesstorsional stress is set up thereby. In the form of girder hereindescribed any torsional stress due toeccentric loading is resolved intothree components. One, the vertical component, is sustained by thevertical or main girder precisely as if the load were appliedsymmetrically. rlhe other two form a couple which tends to rotate thegirder about the horizontal axis through its center of gravity and isresisted by the horizontal trusses.

In the present instance it is designed to locate the trolley whichcarries the hoisting mechanism between the two main beams or girders ofthe bridge and to keep its top near or belou1 the level of the top ofthe bridge, in order to economize head-room as far as practicable. lVhenthe trolley is thus located, the rails upon which its wheels travel aresecured to the inner faces of the two girders, and hence the loadproduces more or less torsional strain thereon. Such torsion, acting asdescribed in the preceding paragraph, causes the upper flanges of thegirders to move inward or toward each other and the lower flanges tomove outward, both very slightly, but sufiiciently to vary the gage ofthe rails. Obviously there is a neutral point or line between the upperand lower flan ges, that is, a point where there is neither inward noroutward movement through torsion. By locating the rails in or besidethis neutral axis I obviate any horizontal movement of the rails inrelation to each other.

Referring now to the drawings, A indicates the main bridge, composed oftwo beams or girders B and C, of such construction as the purposes ofthe crane require and connected at their ends by truck-frames orbridgeends L, only one of which is shown, in Fig. 4. Secured to andprojecting from the upper iiange or chord of each girder B and C is ahorizontal truss D, and secured to and projecting from the lower flangeor chord of each is a similar truss E. The outer chord of each uppertruss D is supported by struts or braces F, which extend from the lowerflange or chord of the main trusses B and C upward and outward, asshown. The outer chord of the lower truss E is suspended from the outerchord of the upper truss D by hangers or suspenders G, which are hererepresented as of angle-iron, but which may be simple rods or flat bars.Angle-iron is preferably employed for reasons of convenience and economyin construction.

The trusses D and E of course involve diagonal braces or struts c andperpendicular struts b between their inner and outer chords. Nodiagonals are, however, used between the outer chords of the upper andlower trusses, since it is neither intended nor desired to producetrusses at such points, but merely to maintain the lower trusses inparallelism with the lower chords of the main beams or girders.

To the inner faces of the main beams or girders B and C are boltedI-beams I, upon the upper tianges of which are secured rails .I toreceive the truck-wheels of a trolley K. The crowns or treads of theserails are located at such height, or at such point between the upper andlower iianges or chords of girders B and C, as will bring themapproximately horizontally opposite the neutral axes of the main beamsor girders B C, which will be at or near the mid-height thereof.

lVheels will of course be provided at the ends of`the bridge.

Vhile the construction of the bridge above set forth is moreparticularly designed for a crane in which the trolley is placed withinthe space between the m ain beams or girders, it is not restrictedthereto, but may have the trolley mounted on its upper surface orcarried in such other manner as may be determined by the exigencies ofany particular case.

It is obvious that the construction may be varied without departing fromthe spirit of my invention, as, for instance, by making the diagonalbraces F to extend from the upper chord of the main girder to the outerchord of the lower truss, as in Fig. 5, thus acting as suspensioninstead of compression braces, or the upper horizontal truss may beattached to the main girder below instead of directly to its upperfiange, as in Fig. G, in which case angle-plates c or equivalent meansof attachment will be provided. Such differences do not materially alterthe stresses set up by the various forces acting on the girder.

As above stated, I have represented the trussing as formed ofangle-iron, though not intending to restrict myself thereto. When used,it may be bolted or riveted together in the manner illustrated in Figs.5, 6, and 7, in which latter figure the vertical members G are shown ofL form in cross-section, whereby strength and stiffness aresecured,together with good bearing-surfaces and proper body throughwhich to rivet.

Ilaving thus described my invention, what I claim is l. A crane-bridgeprovided with a lateral support consisting of two horizontal trusses,one projecting from its upper and the other projecting from its lowerchord or flange, di-

IOO

agonal struts or braces extending from the bridge proper to the outerchord of one of the trusses, and uprights connecting the outer chords ofthe two trusses.

5 2. Iua crane-bridge, the combination with two separated beams orgirders each provided with a horizontal truss, of trolley-supportingrails carried by the inner faces of said beams or girders, in line withthe neutral axes thereof r o as regards the torsion of said beams orgirders. 3. In a crane-bridge, the combination of two separated beams orgirders each having parallel upper and lower chords; horizontal trussesapplied to the outer faces of said I5 beams; and rails carried by theinner faces IVitnesses:

J. G. EMERY, J r., CHAs. L. GRIFFIN.

